Air valve



FIG. 1 is a front elevation view thereof;

FIG. 2 is a rear elevation view thereof;

FIG. 3 is a right side perspective view thereof;

FIG. 4 is a left side perspective view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof. 

The ornamental design for an air valve, as shown and described. 